Pick through the beans to remove anything that shouldn't be there.
Rinse, drain, and put into a pot, add the onion, garlic, and hot water to come several inches above the surface of the beans, and bring to a simmer.
Continue simmering until the beans are tender but not soft (not al dente either).
Add salt and cook for 5 more minutes.
Drain and use the broth for a vegetable soup.

Crumble the leaves, removing the tough stems, into an electric coffee grinder and blend to a powder.

Put the drained beans into a food processor and blend to a textured paste, adding the avocado powder.
The paste should be quite dry.